Westerbeke 7.6 kw EDT Operator's Manual page 42

ALTERNATORS TESTINGJTROUBLESHOOTING
TESTING THE ALTERNATOR
A
CAUTION:
Before starting the engine make
certain that everyone is clear of moving parts! Keep
away from sheaves and belts during test procedures.
1. Start the Engine.
2. After the engine has run for a few nrinutes, measure the
starting battery voltage at the battery terminals using a
multimeter set on DC volts.
a. If the voltage is increasing toward 14 volts, the
alternator is working.
b.Ifthe voltage remains around 12 volts, a problem
exists with either the alternator or the charging circuit;
continue with Steps 3 through 6L
MEASURING
BATTERY VOLTAGE
(ENGINE RUNNING)
3.
'fum
off the engine. Inspect all wiring and connections.
Ensure that the battery terminaIs and the engine ground
connections are tight and clean
4. If a battery selector switch is in the charging circuit,ensure
that it is oil the correct setting.
5. Check the battery voltage. If your battery is in gQod .
condition the reading should be 12
to
13 volts.
MEASURING
BATTERY VOLTAGE
ENGINE OFF)
TESTING THE
nllTDIIT
1. Connect the positive probe to the output terminal B and
connect the negative probe to ground.
2. Wiggle the engine wiring hamess while observing the
vol1meter. The meter should indicate the approximate
battery voltage, and should not vary. If no reading is
obtained, or if the reading varies, check the alternator
output circuit for loose or dirty connections or
damaged wiring.
3. Start the engine.
4. Repeat the same measurement, the negative probe to
ground, the positive probe to B with the engine running.
The voltage reading should be between 13.5 and 14.5
volts. If your alternator is over or under-charging, have
it repaired at a reliable service shop.
5. If the previous test reads ouly battery voltage at
tenninal B, use the meter to measure the DC excitation
tenninaI. If 12 volts is not present at exciter tenninal R,
inspect the wiring for breaks and poor GOnnections.
Jump 12 volts from a 12 volt source (such as the
battery) and operate the alternator. If the voltage output
is 13-14 volts; .. then the alternator is OK.
TESTING THE OUTPUT
CIRCUIT ENGINE RUNNING
#100RANGEB
TO
STARTER
.ULtNUiIU
'..v'
WESTERBEKE
#16 VlOLETR
TO K·3 RELAY
Engines & Generators
32